Sheet metal corner for duct flanges

ABSTRACT

A corner flange connection member for joining flanges of duct sections, includes two leg portions joined together in an angular relationship by a corner portion, the connection member being substantially flat and including at least one opening for receiving a fastening member having a threaded portion, the threaded portion having a root diameter, the opening being defined by two joined and offset partially rounded openings, at least one of the offset partially rounded openings having a sectional extent between opposite sides thereof about equal to the root diameter of the threaded portion of the fastening member, the offset being about equal to a thread height of threads of the threaded portion of the fastening member, and the sides of the offset openings being joined generally tangentially. The opening or openings can be located in the corner portion or one or both of the leg portions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Pat. application Ser. No.12/466,632, filed May 15, 2009, now U.S. Pat. No. 8,172,280, dated May8, 2012, which is a non-provisional application claiming priority toprovisional Patent Application Ser. No. 61/053,772 filed May 16, 2008,each of which is incorporated herein by reference in its entirety.

BACKGROUND OF INVENTION

The present invention relates generally to duct assemblies fortransporting pressurized fluid in buildings such as ductwork for HVACsystems and, more particularly, to various embodiments of a cornerflange connection member for placement into corners defined by channelflanges associated with HVAC and other types of ductwork and the methodfor attaching such corner flange connection members to the ductworkchannel flanges including certain improved high speed fastenerconnectors.

Duct assemblies used to transport pressurized fluid in buildings such asforced air HVAC systems are conventionally formed in sections andsecured together to form longer spans as needed. A duct section istypically formed of sheet metal into a rectangular shape having foursides and vent or seamed corners at the intersections of the sides. Aflange extends essentially perpendicularly outward from each side atboth ends of the duct section. Duct sections are positioned end-to-endsuch that the flanges of one duct section align with the flanges of anadjacent duct section and the aligned duct flanges are fastened togetherto form the overall duct assemblies. The flanges which are formed aspart of each duct section are not continuous. Rather, there are gaps ateach location on the duct sections where adjacent flanges meet formanufacturing convenience. These typically occur at the four corners ofthe top and bottom sections of a particular duct section. Corner piecesor corner flange connectors are typically inserted into channels formedin each duct flange such that they span the corner gap at each locationon the duct section where adjacent flanges meet. When the duct sectionsare positioned end-to-end, the corner pieces of one duct section arealigned with corner pieces of the adjacent duct section. Fasteners arethen inserted through holes extending through the corner pieces to clampthe duct sections together. Typically, a single bolt with a washer andnut are used to complete the duct flange connector. Frequently, gasketsare placed between aligned duct flanges to achieve an airtight seal andclips or screws are used to hold the aligned flanges together betweenthe corner pieces.

One typical corner flange connector or angle plate is disclosed in U.S.Pat. No. 5,342,100 wherein the angle plate is pressed into duct channelflanges which are formed with return side wall bends at their free endsto hold the angle plate in the duct channel flange when the return sidewall bends of the flanges are crimped over such angle plate. This angleplate likewise includes upstanding projections or the equivalent thereofprojecting in a common direction and being of a height to hold adjacentplates parallel and spaced apart from each other when stacked one on topof the other thereby preventing nesting and permitting the sliding ofsingle plates off the bottom of a stack of plates for use in anapparatus for automatically installing angle plates at the corners ofductwork. This snap or pressing connection of the corner plate into theduct channel flange does not always produce a completely secureconnection, even when crimping is used. Not only does this techniqueallow the corner plates to become separated from the flanges moreeasily, it also allows adjacent flanges of the duct assembly to moveindependently of each other. If the corner plates move independentlyfrom the flanges, adjacent flanges of the duct assembly can likewisemove independently from each other permitting the duct sections to movewith respect to each other thereby allowing fluid or air to leak frombetween the joints. If these corner plates become loose or actuallyseparate from the flanges, additional time is required to reinsert andfasten the corner pieces in the appropriate duct channel flanges and toreattach the adjacent duct sections. A corner flange connection memberwhich achieves a more robust connection and which is easier to installis desirable.

Another known corner member and method for connecting adjacent ductassemblies is disclosed in U.S. Pat. No. 6,471,256. This corner flangeconnection member requires no pressing or crimping and utilizes nuts andbolts to complete the connection. The joint is formed by passingstandard fasteners through a corner flange connection member associatedwith one duct section, through integral channel flanges associated withthe adjacent duct sections which are arranged in end-to-end relationshipto each other, and through a corner flange connection member associatedwith the other duct section. The act of installing the fasteners tightlypulls together the duct flanges and makes an integral connection betweenthem. The use of machine screws, without nuts, which bite into thematerial of the duct flange when driven through holes associated withthe respective arm portions of the connector member and throughpre-formed holes associated with the duct flanges thereby forming athreaded inner connection therebetween is likewise disclosed.

Still further, as likewise disclosed in U.S. Pat. No. 6,472,256, cornerplates can also be attached to the duct channel flanges by deformingmaterial of the duct flanges through pre-formed holes associated withthe corner plates. In this instance, no screws, nuts or bolts areutilized in the joinder method. Other connector member configurationsand methods for attaching adjacent duct sections together are likewisedisclosed in U.S. Pat. No. 6,471,256. Although all of these cornermembers and connection techniques improve the stability and rigidity ofconnecting adjacent duct sections, an easier, faster, and more efficientmethod for making such connections as well as use of a corner flangeconnection member which applies greater clamping force to the ductflanges is desirable. In addition, use of a corner flange connectionmember, improved fasteners and a method of attaching adjacent ductsections which can accommodate for damage and/ormalformation/misalignment occurring to the duct channel flanges duringmanufacturing, transportation and/or assembly without the need forextensive and expensive corrective measures is likewise desirable.

Accordingly, the present invention is directed to overcoming one or moreof the problems as set forth above.

SUMMARY OF INVENTION

The present invention relates to various embodiments of an improved highspeed corner flange connection member which is specifically shaped anddesigned to increase the clamping force applied to adjacent duct flangeswhen adjacent duct sections are connected together, and which cornerflange connection members are both nestable and slidable for use withautomated corner installing machines such as those made by IowaPrecision Industries, Lockformer, and others. The present corner flangeconnection members include a pair of integrally formed leg portionswhich are bowed or otherwise bent such that when the corner flangeconnector member is initially positioned within the duct channel flange,only portions of the corner flange connection member rest upon the ductchannel flange while other portions are spaced from or elevated abovethe duct channel flange so as to form a spring-type biasing action whena pair of opposed corner flange connection members are drawn together bythe action of the fastening members as will be hereinafter explained.The pair of leg members are joined together at right angles to form anL-shaped member, the intersection of the leg members forming a cornerportion of the connection member. In one embodiment, the corner portionincludes a pair of openings, one opening being larger than the otheropening, one opening being characterized as a clearance hole while theother opening is characterized as a tap hole or a threadable hole. Inanother embodiment, the openings associated with the corner portion areof a similar diameter.

The corner portion of the present corner flange connection memberlikewise includes a pair of spaced apart creases or bends from which theleg portions are bent thereby allowing the corner portion to remainrelatively flat while allowing the respective leg portions to beangularly oriented relative thereto. This configuration establishes thebowed portion of the present corner flange connection member and enablesthe present corner flange member to apply a greater clamping pressure tothe duct channel flanges as adjacent duct sections are fastenedtogether. In this regard, the corner flange connection member associatedwith the duct channel flange of one of the adjacent duct sections willbe positioned and oriented relative to the corner flange connectionmember positioned within the duct channel flange of the adjacent ductsection such that, in one embodiment, the clearance hole of one cornerflange connection member will be aligned with the tap hole associatedwith the opposed corner flange connection member of the adjacent ductsection. As a result, the act of installing and threading a fastenermember through an aligned clearance hole and tap hole associated withopposed corner flange connection members will tightly pull together theadjacent duct channel flanges and will apply a clamping force to suchduct channel flanges as the fastening member is threaded therethroughwithout the use of the conventional bolt, nut and washer combination.The bowed configuration of the present corner flange connection memberapplies a greater clamping force to the adjacent duct sections ascompared to the known corner members or angle plates for reasons whichwill be hereinafter explained. In this regard, the tap hole associatedwith the corner portion of the present corner flange connection memberis sized so as to receive a pilot portion associated with the fastenermember but which hole is smaller than the threaded portion of thefastener member. In contrast, the clearance hole is sized and shaped soas to be larger than the threaded portion of the fastener member. As aresult, as the fastener member is driven first through the alignedclearance hole and then through the aligned tap hole associated withadjacent opposed corner flange connection members, the fastener memberwill first pass completely through the clearance hole of the firstcorner flange connection member and will bite into the materialassociated with the opposed corner flange connection member surroundingthe tap hole. This action forms a threaded inner connection therebetweendrawing the second corner member towards the first corner member. As thefastener member is driven through the corner members, the adjacent ductsections are likewise driven together by the action of the fastenermember into a tight substantially sealing relationship at the jointbetween the duct sections. Since the tap hole is smaller than thethreaded portion of the fastening member, the fastening member will bitemore deeply into the material associated with that particular cornerflange connection member thereby tightly drawing the two cornerconnection members into sealing engagement with each other. Ifnecessary, a second fastening member can be threaded through therespective corner portions of adjacent corner flange connection membersassociated with adjacent duct sections from the opposite side thereofthereby further securing the corner flange connection members to theadjacent duct sections. Small duct sections can be held with onefastening member, while larger duct sections can use two or morefastening members.

In those applications where additional strength and rigidity isrequired, the respective leg portions associated with the present cornerflange connection members may likewise include optional holes forreceiving additional fasteners for clamping the duct channel flangestherebetween. In one embodiment, one leg portion may include a clearancehole while the other leg portion would include a tap hole. In thisparticular configuration, aligned pairs of corner flange connectionmembers will be positioned within adjacent duct channel flanges suchthat a clearance opening associated with the leg portion of one of theopposed pairs of connector members will be positioned in alignment withthe tap hole associated with the leg portion of the other opposedconnector member. In still another embodiment, the openings associatedwith the respective leg portions may be of the same diameter or othershape such as rectangular or square. Regardless of whether clearanceopenings and tap openings are utilized in a particular embodiment, orwhether the openings associated with the corner portion and leg portionsare of similar diameters or other similar shapes, a strong tightconnection between adjacent duct sections is achieved through the use ofthe high speed fasteners associated with the present invention as willbe hereinafter explained, and through the application of a greaterclamping force to the duct channel flanges sandwiched therebetween dueto the bowed configuration of such corner flange connection members.

In still other embodiments of the present corner flange connectionmember, the bowed configuration of such corner members can be eliminatedand such corner flange connection members can be made so as to besubstantially flat or planar. In this particular configuration, in oneembodiment, the corner portion of such connector members may include aclearance hole and a tap hole as previously explained, and one legportion may include a clearance hole while the other leg portionincludes a tap hole.

In still another embodiment, the openings associated with the cornerportion of a substantially flat or planar corner member may be of thesame diameter or other shapes, and the openings associated with therespective leg portions may be of the same or a different similardiameter or other shapes. In this regard, a rectangular opening, anoblong opening or other shaped opening may also be used. In theseparticular embodiments, a strong tight sealing connection betweenadjacent duct sections is achieved through the use of aligned clearanceholes with tap holes, and/or through the use of the high speed fastenermembers associated with the present invention as will be hereinafterfurther explained.

Still further, although no pressing is required for initially insertingany of the present corner flange connection members within therespective duct channel flanges, the present connection members aresized and shaped so that crimping of the adjacent duct channel flangesonto the present corner flange connection members is likewise possibleto further strengthen the joinder therebetween. Since the present cornerflange connection members are substantially smooth and do not includeupstanding side walls or any projections or protrusions similar to theprojections associated with the angle plate disclosed in U.S. Pat. No.5,342,100, the present corner flange connection members are bothstackable and nestable within an automated corner plate installingmachine and such corner flange connection members are likewise easilyslidable from the bottom of a stack for use with such automated cornermachines. In addition, since the present corner members include noupstanding side walls or side flanges, crimping is substantially easiersince only the side wall of the duct channel flange need be crimped.

Still further, although traditional sheet metal screws or standard nutsand bolts can be used in clamping together adjacent duct sections, thepresent invention also includes the use of high-speed connector membersin the form of a piloted self-tapping bolt, a piloted bolt incombination with a standard nut, a standard bolt or carriage bolt incombination with a piloted nut or piloted washered nut, a pilotedself-tapping bolt with a relief portion between the head and threadedportion, a piloted carriage bolt in combination with a piloted nut, anda special sheet metal fastener, all of which provide improved drawingaction. Each of these high-speed fastening connectors greatly improvesthe time required to accomplish the joinder and eliminates the use ofclumsy hex nuts and washers. These improved fastening members likewisesubstantially eliminate cross-threading and misalignment of the nut andbolt combination and, importantly, all of these fastening members can bequickly inserted through the use of a battery powered drill or otherpower tool.

BRIEF DESCRIPTION OF DRAWINGS

For a better understanding of the present invention, reference may bemade to the accompanying drawings.

FIG. 1 is a partial perspective view of a typical corner portion of aduct section having duct channel flanges into which the present cornerflange connection members are inserted.

FIG. 2 is a top plan form view of one embodiment of the present cornerelements constructed in accordance with the teachings of the presentinvention.

FIG. 3 is a front elevational view of the corner element of FIG. 2.

FIG. 4 is a partial perspective view of a pair of duct sections joinedtogether using the corner element of FIGS. 2 and 3.

FIG. 5 is a partial top plan form view of a pair of the connectorelements of FIGS. 2 and 3 positioned within adjacent duct channelflanges showing the alignment of the respective holes associatedtherewith including use of a slot associated with each duct channelflange to address misalignment issues.

FIG. 6 is a front elevational view of a pair of the present connectorelements of FIGS. 2 and 3 positioned within aligned duct channel flangesshowing the bowed configuration of the corner elements.

FIG. 7 is a side elevational view of one embodiment of a high speedfastener member for use with the present connector elements constructedin accordance with the teachings of present invention.

FIG. 8 is a partial front elevational view of the assembly of FIG. 4showing the fastener member of FIG. 7 inserted and threaded through thealigned clearance and tap holes associated with the corner portion ofthe corner elements of FIGS. 2 and 3.

FIG. 9 is a partial perspective view similar to FIG. 4 illustrating thejoinder of adjacent duct sections using the corner elements of FIGS. 2and 3 including using fastener members through the openings associatedwith the leg portions of the connector elements.

FIG. 10 is a side elevational view of another embodiment of a high speedfastener for use with the present corner elements constructed inaccordance with the teachings of the present invention.

FIG. 11 is a side elevational view of another embodiment of a high speedfastener member for use with the present corner elements constructed inaccordance with the teachings of the present invention.

FIG. 12 is a side elevational view showing the corner elements of FIGS.2 and 3 in a stackable/nestable arrangement in a typical cornerinstalling machine.

FIG. 13 is a top plan form view of another embodiment of a cornerelement constructed in accordance with the teachings of the presentinvention.

FIG. 14 is still another embodiment of a high speed fastener member foruse with the present corner elements constructed in accordance with theteachings of the present invention.

FIGS. 15A-C are side elevational views showing joinder of adjacent ductsections using the corner element of FIG. 13 and the fastener member ofFIG. 14.

FIG. 16 is another embodiment of the present corner element constructedin accordance with the teachings of the present invention.

FIG. 17 is still another embodiment of the present corner elementconstructed in accordance with the teachings of the present invention.

FIG. 18 is still another embodiment of the present corner elementconstructed in accordance with the teachings of the present invention.

FIG. 19 is still another embodiment of a high speed fastener member foruse with the corner element of FIG. 18.

FIG. 20 is still another embodiment of the present corner elementconstructed in accordance with the teachings of the present invention.

FIG. 21 is still another embodiment of a high speed fastener member foruse with the corner element of FIG. 20.

FIG. 22 is an exploded view showing the formation of the corner openingassociated with the corner element of FIG. 20.

DETAILED DESCRIPTION

Referring to the drawings wherein like numerals refer to like parts,FIG. 1 illustrates the lower corner of a typical duct section 10 andshows the specific details of the duct channel flange 12 formed atopposite ends of the duct panels 14. Each duct channel flange 12includes a base member 16 which extends transversely outwardly from eachend portion of each duct panel 14. The base member 16 terminates in aside wall or side flange 18 which extends parallel to the respectiveduct panels 14 and may be selectively doubled inwardly or outwardly uponitself to form a return bend 20 at its free end. The duct channelflanges 12 are adapted to receive the various embodiments of the cornerflange connection members of the present invention as illustrated inFIGS. 2-5, 13, 16 and 17.

FIG. 2 illustrates one embodiment 22 of the present corner flangeconnection member or corner element which is basically L-shaped inconfiguration and includes a pair of integrally formed leg portions 24and 26. The leg portions 24 and 26 are integrally joined together andintersect at right angles at corner portion 28. Corner portion 28includes a pair of spaced-apart openings 30 and 32, opening 30 beinglarger in diameter than opening 32, opening 30 being characterized as aclearance hole while opening 32 is characterized as a tap hole. In thisregard, as will be hereinafter further explained, the clearance hole 30is of a diameter greater than the diameter of the threaded portion ofthe fastening member positioned therethrough for joining adjacent ductsections as will be hereinafter explained whereas, to the contrary, taphole 32 is of a diameter smaller than the diameter of the threadedportion of the fastening member utilized to connect adjacent ductsections. In addition, the corner portion 28 of the present cornerflange connection member 22 likewise includes a pair of spaced creasesor bends 34 and 36 wherein the respective leg portions 24 and 26extending away from the creases 34 and 36 towards their respectiveterminal end portions are bent or angularly deflected about such creasesdownwardly as best illustrated in FIG. 3. The bent or angularlydeflected leg portions 24 and 26 present a bowed shaped connectionmember when positioned on a substantially flat or planar surface asillustrated in FIG. 3 wherein the corner portion 28 remains relativelyflat and substantially parallel to a corresponding planar surface suchas the surface 38 illustrated in FIG. 3, and the corresponding legportions 24 and 26 are angularly oriented or bent downwardly alongcreases 34 and 36 as likewise best illustrated in FIG. 3. This bowedconfiguration supplies a clamping pressure to the duct channel flangeswhen a pair of duct sections are joined together in end-to-endrelationship as will be hereinafter further explained. It is alsorecognized that the creases or bends 34 and 36 may be located anywherealong the length of each respective leg portion 24 and 26 such that atleast a portion of each leg portion extending away from its respectivecrease or bend will be bent or angularly deflected about such crease orbend as explained above. Still further, it is also recognized that theentire corner flange connection member 22 may be one continuous curve orbow such that the corner portion 28 no longer remains substantially flatand the creases or bends 34 and 36 merge at the center of corner portion28 and the corner portion 28 forms one continuous curve or bend with legportions 24 and 26. As best seen in FIG. 3, this embodiment would havecorner portion 28 slightly bowed between the creases 34 and 36. The keyto this aspect of the present invention is the bowed, curved or arcconfiguration of the corner flange connection member 22, however suchbowed configuration is achieved.

Still further, the leg portions 24 and 26 of the present corner flangeconnection member 22 may likewise each include a respective opening 40and 42 as illustrated in FIG. 2. Here again, opening 40 is characterizedas a clearance opening and would have a diameter greater than thediameter of the threaded portion of the fastening member positionedtherethrough, and opening 42 is characterized as a tap hole and wouldhave a diameter smaller than the diameter of the threaded portion of thefastening member positioned therethrough as likewise will be hereinafterfurther explained. The openings 40 and 42 are optional and may beutilized to add additional strength and stability to the joinder of twoduct sections as will be hereinafter further explained.

FIGS. 4-8 illustrate the joinder of two duct sections 10 fortransporting pressurized fluid assembled using the corner flangeconnector members 22 described above. The duct sections 10 arepositioned in end-to-end relationship as shown such that the ductchannel flanges 12 extending outwardly from the respective ends of theduct panels 14 face each other thereby defining aligned duct channelflange pairs such that the corners and sides of the duct sections arealigned. As best shown in FIG. 1, at each corner of the duct sections 10there is formed by the duct channel flanges 12 a square notch or opening44. The duct assembly illustrated in FIG. 4 is fastened together throughthe use of a pair of corner flange connection members 22 positionedwithin the duct channel flanges 12 at each of the aligned corners of therespective duct sections 10. Each connector pair thereby comprises apair of separated corner flange connector members 22 spanning adjacentduct flanges 12 of each duct section 10. The pair of corner flangeconnection members 22 are positioned on opposing faces of each flangepair 12 such that the duct channel flange pair are positioned betweenthe connector elements 22. When the corner flange connector members 22are initially positioned within the duct channel flanges 12 asillustrated in FIG. 4, such corner flange connector members 12 will bepositioned and oriented relative to their respective duct channelflanges as illustrated in FIG. 6. In other words, the opposed connectorelements 22 will be bowed as illustrated and only portions of therespective leg portions 24 and 26 will be in initial contact with therespective duct channel flanges 12. In this regard, it is also importantto note that the opposed corner connector elements 22 are positioned inopposed relationship to each other such that the clearance hole 30associated with one connector element 22 will be positioned in alignmentwith the tap hole 32 associated with the opposed connector element 22.This will enable one or two fastener members to be positioned within thecorresponding clearance holes 30 associated with the opposed connectorelements 22 for engagement of the duct sections 10 as will behereinafter further explained. The fastener member will extend throughat least one of the aligned openings 30 and 32 extending through eachcorner element 22 of the pair adjacent the corner of the duct sections10. The alignment of the respective holes 30 and 32 associated with theopposed connector elements 22 within the corresponding duct channelflanges 12 is illustrated in FIG. 5 and proper alignment will alwaysoccur due to the bowed configuration of the corner element 22, that is,so long as the downwardly extending leg portions 24 and 26 are alwayspositioned extending downwardly in the duct channel flange.

Although a conventional fastener member in the form of a conventionalnut and bolt fastener can be utilized to quickly join the pairedconnector elements 22 and the adjacent duct sections 10 in end-to-endrelationship, another aspect of the present invention relates to the useof a high-speed connector member in the form of a piloted self-tappingbolt 46 illustrated in FIG. 7. The fastener 46 includes a head portion48, a threaded portion 50, and a piloted portion 52. The piloted portion52 does not include threads and includes a beveled tip 54 for guidingand aligning the fastener 46 within a respective opening. In theembodiment illustrated in FIGS. 4, 6 and 8, the fastener 46 is sized anddimensioned in accordance with the diameter of the respective openings30 and 32 associated with the present corner flange connector member 22.In this regard, as best illustrated in FIG. 8, the fastener 46 is firstinserted through the clearance opening 30 associated with one of theopposed connector elements 22. Since the clearance opening 30 has adiameter greater than the diameter of the threaded portion 50 offastener 46, the fastener 46 will easily slide through the opening 30 insearch of the opposed tap opening 32 associated with the other connectorelement 22. Since the piloted portion 52 of the fastener 46 has adiameter which is less than the diameter of threaded portion 50, andsince the piloted portion 52 is of a smaller diameter, the pilotedportion 52 of fastener 46 will register with and extend through thecorresponding tap opening 32 which is sized to receive the same.However, since the diameter of the tap hole 32 is smaller than thediameter of the threaded portion 50 of fastener 46, the fastener 46 willbite into the material of the corner portion 28 surrounding tap hole 32as the fastener 46 is driven through the opening 32. This forms athreaded inner connection between the opposed pairs of corner elements22 as the fastener 46 is driven through the respective aligned openings30 and 32 and, as the fastener 46 bites into the opposite corner element22, it will draw the opposed corner elements 22 into engagement witheach other. The fastener 46 will pass through the first corner elementand will draw the second opposed corner element tightly against it witha consistent force due to the threaded portion 50 clearing the firstcorner element. Since the integral duct channel flanges 12 associatedwith adjacent duct sections 10 are sandwiched between the opposed pairof connector elements 22, as the fastener 46 is driven through theopenings 30 and 32, both the corner portions 28 of the corner elements22 as well the duct sections 10 sandwiched therebetween are drawntogether by the action of the fastener 46 into a tight sealingrelationship at the joint between the duct sections.

Importantly, since the opposed connector elements 22 are bowed as bestillustrated in FIGS. 3 and 6, and as explained above, as the fastener 46is driven through the respective pair of corner elements 22, the cornerportions 28 of the opposed corner elements 22 are likewise drawntogether by the action of the fastener 46 thereby exerting a clamping orbiasing force against the respective duct channel flanges 12 whichfurther serves to form a tight sealing relationship at the joint betweenthe duct sections. The bowed configuration of the opposed cornerelements 22 thereby apply a clamping pressure to the duct flanges 12 asthe fastener 46 is driven through the respective openings 30 and 32thereby applying an additional biasing force against the respective ductflanges further enhancing the joinder therebetween. As the fastener 46is driven through the opposed pair of corner elements 22, the cornerportions 28 of each opposed corner element 22 is pressed into a nearlyflat condition within its respective duct channel flanges and therespective corner portions 28 are likewise drawn together as illustratedin FIGS. 4 and 8. Depending upon the particular duct application, theuse of a single fastener member 46 may be sufficient for certain lowpressure HVAC applications. For higher pressure applications, anadditional fastener member 46 may be driven through the other alignedpair of openings 30 and 32 associated with the corner portions 28 of theopposed corner elements 22 from the opposite side of the connectedcorner element pairs if necessary. The spacing between the respectiveopenings 30 and 32 associated with the corner portion 28 of each cornerflange connector member 22 is such that fastener member 46 can be driventhrough an aligned pair of connector elements 22 from opposite sidesthereof without interference. In certain applications, the use of one ortwo fasteners 46 driven through the opposed corner portions 28 willprovide sufficient clamping force to hold the aligned duct sections 10in sealing engagement.

In this regard, it is recognized that each of the four corners of thealigned duct sections 10 would be fastened together using connectedpairs of connector elements 22 as described above with respect to FIGS.4-6 and 8 using fastener member 46. Although other suitable fasteningdevices may be used in connecting the aligned opposed pairs of connectorelements 22 at each duct corner such as sheet metal screws or machinescrews (not shown), it is believed that the use of the high-speedfastener member 46 will be more efficient, will require less time forinstallation, will prevent cross-threading and mis-threading associatedwith conventional nut and bolt fasteners, and the fasteners 46 can bequickly inserted through the use of a power drill. In this regard, thehead portion 48 of the fastener 46 is adapted for use with conventionaltype power drills. This is not necessarily true with respect to sheetmetal screws or machine screws.

As will be understood by those skilled in the art, the fasteners 46connecting the paired corner elements 22 and the paired duct flanges 12not only connect the aligned connector pairs 22 but also directlyconnect adjacent duct flanges 12 of each duct section 10 to each otherto significantly strengthen the assembly.

In those applications where additional strength and rigidity arenecessary for connecting adjacent duct sections 10, optional holes 40and 42 can be associated with the leg portions 24 and 26 as illustratedin FIGS. 2, 5 and 9. Again, if the clearance hole 40 and tap hole 42 areutilized in association with the pair of leg portions 24 and 26 as bestillustrated in FIG. 2, the positioning of the opposed pair of connectorelements 22 within the duct channel flanges 12 as illustrated in FIG. 9will be such that a clearance opening 40 associated with leg portion 24of one of the opposed pairs of connector elements 22 will be positionedin alignment with the tap hole 42 associated with leg portion 26 of theother opposed connector element 22.

Often times the duct channel flanges are provided with holes or openingsfor accomplishing this additional joinder. Such flange holes aretypically spaced from the duct section corners a predetermined distancein conformity with the positioning of the additional openings 40 and 42associated with the present connector elements 22 as well as with otherconventional corner or angle plates. Due to manufacturing tolerances,damage to the duct channel flanges during shipping, and other factors,the alignment of duct channel flange openings with the openings 40 and42 often do not occur. This out-of-alignment situation is overcome byanother aspect of the present invention wherein a slot 56 isappropriately positioned in the duct channel flange 12 at apredetermined distance from the duct corner as illustrated in FIG. 5.Use of the slot 56 as compared to a single hole or opening in the ductchannel flange substantially eliminates the misalignment issue andallows the respective connector element leg openings 40 and 42 to beproperly aligned since the slot 56 is of sufficient length or size tocapture both openings 40 and 42 associated with the opposed leg portionsof connector elements 22 therewithin thereby eliminating any contact orinterference with the duct channel flange. Use of the slots 56 likewiseenables a user to move the corner elements 22 even after installation byhammering inward or outward on the respective corner element or the ductwall adjacent thereto so as to move the holes 40 and 42 into alignmentwith each other when the duct section is out of alignment due to slightsize differences or other factors as discussed above.

In similar fashion, a fastening member such as the high-speed fastener46 is inserted first through the clearance opening 40 associated withone leg portion 26 of the aligned pairs of connector elements 22, thenthrough the aligned slot 56 of the duct channel flange 12, and finallythrough the tap opening 42 associated with the opposed leg portion 24 ofthe aligned pair of connector elements 22 so as to complete theconnection therebetween. The fastener 46 will bite into the materialsurrounding the tap hole 42 as previously explained during the fasteningprocess. The width of the slots 56 should be at least as wide as thediameter of the clearance hole 40 for receiving the threaded portion 50of the fastener 46.

In the particular embodiment illustrated in FIG. 9, at least onefastener 46 is utilized through aligned openings 30 and 32 associatedwith the corner portion 28 of the opposed pair of connector elements 22and a fastener 46 is likewise used for each of the two opposing legportions 24 and 26 associated with the opposed pair of connectingelements 22. As illustrated in FIG. 9, only three fasteners 46 are usedfor the joinder. It is also recognized that a fourth fastener 46 couldlikewise be utilized through the corner portions 28 of the opposed pairof connector elements 22 as previously described with respect to FIG. 4.In this situation, there would be four fasteners 46 driven through eachpair of connector elements 22 associated with the four corners of thealigned duct sections 10 for additional strength if needed. The precisenumber of holes and fasteners associated with both the leg portions 24and 26 and the corner portion 28 of the present connector element 22 mayvary and may include additional openings 30 and 32, 40 and 42 withoutdeparting from the spirit and scope of the present invention.

As best illustrated in FIGS. 2 and 5, and as explained above, thefastener 46 will generally not bite into the material of the cornerelement leg portion 26 or the duct channel flange 12 when passingthrough the clearance hole 40 and slot 56, but will bite into thematerial of the opposing corner element leg portion 24 around thesmaller tap hole 42. In this way, the fastener 46 again uses the opposedleg portions of the corner elements 22 to further clamp together theduct channel flanges 12 of the respective duct sections 10. Of course,the fastener 46 may bite into the duct channel flange 12 because of aslight misalignment of the slot 56 with the openings 40 and 42, and theslot 56 may be made smaller to promote direct inner connection of thefasteners 46 with the duct channel flange 12 while remaining within thescope of the present invention. Nevertheless, the possibility ofmisalignment of the slots 56 and the corner element leg openings 40 and42 are greatly reduced since the length of the slots 56 obviate manymisalignment scenarios and likewise allow for correction of any slightmisalignment issues as previously explained.

Although fastener 46 is preferred because it does not require the use ofan additional nut or washer and it is specifically designed for quickand easy insertion with a power drill, another aspect of the presentinvention is related to the use of fastener 58 illustrated in FIG. 10.Fastener 58 comprises a high-speed piloted bolt 60 in combination with astandard nut 62. The bolt 60 includes a head portion 64, a threadedportion 66, and a piloted portion 68 similar to fastener 46. Likefastener 46, the piloted portion 68 is of a diameter smaller than thethreaded portion 66 and is of a diameter smaller than the tap hole 42associated with leg portion 24 of corner element 22. Bolt 60 willfunction in the same manner as fastener 46 with respect to engaging theclearance hole 40 and biting into the material surrounding the tap hole42, and the threaded portion 66 and pilot portion 68 are sized andshaped so as to be compatible with the size and shape of the clearanceand tap holes 42 and 40 as discussed above. In addition, the pilotportion 68 of the bolt 60 enables a standard nut such as the nut 62 tobe guided into perfect threadable engagement with the threaded portion66 thereby substantially eliminating mis-threading of the nut 62 ontothe bolt 60 as well as substantially eliminatingcross-threading/misalignment typically associated with threading astandard nut onto a standard bolt. The use of the piloted portion 68 onbolt 60 again speeds up the connection process; it provides for properthread engagement between the nut 62 and the threaded portion 66 of bolt60; and it provides for a high-speed connection through the use of apower drill. The spacing of the holes 30 and 32 associated with thecorner portion 28 of the present corner elements 22 are likewisesufficiently spaced so as to allow the fastener 58 to be inserted fromopposite sides of an opposed pair of corner elements 22 when positionedfor joining adjacent duct sections 10 as previously described withrespect to FIG. 4.

FIG. 11 illustrates still another embodiment 70 of a high-speed fastenermember for use with the present corner elements 22, the embodiment 70including a standard bolt 72 and a piloted nut 74. The standard bolt 72includes a head portion 76 and a threaded portion 78 and the piloted nut74 includes a non-threaded cavity 80 and a threaded cavity 82. Thenon-threaded cavity 80 is of a diameter larger than the threaded portion78 of bolt 72 and larger than the threaded cavity 82 and extends along aportion of the overall length of the piloted nut 74 as illustrated inFIG. 11. The piloted nut 74 could also be a piloted washered nut. Theslightly oversized non-threaded cavity 80 serves as a guide mechanismfor properly orienting the threaded portion 78 of the standard bolt 72into the nut 80 before engaging the threaded cavity 82. Like the pilotedportions 52 and 68 associated with fasteners 46 and 58, the non-threadedcavity 82 allows the nut 76 to be properly positioned relative to thethreaded portion 78 thereby again substantially eliminatingcross-threading and misalignment issues in engaging the nut 74 with thebolt 72. This again provides for a quick, easy, and high-speedconnection between the bolt 72 and the nut 74 including connectionthrough the use of a power drill. The nut 74 may also have a flat washershape attached or otherwise associated with one end portion thereof foruse with slotted or rectangular openings.

Use of the fasteners 58 (FIG. 10) and 70 (FIG. 11) are preferred overthe uses of standard nuts and bolts in that the piloted portion 68 andnon-threaded cavity 80 provide for mating the respective bolts 60 and 72with their corresponding nuts 62 and 74 in a fast and efficient mannerwith accurate alignment of the corresponding threads thereby precludingcross-threading and other misalignment issues so that a power tool canbe used without the need to start the threading process by hand beforeusing the power tool. All of the fasteners associated with the presentinvention, namely, fasteners 46, 58 and 70 have advantages as explainedabove over the use of standard nuts and bolts, sheet metal screws andmachine screws which are typically used in connecting adjacent ductsections. Use of the clearance holes 30 and 40 and the tap holes 32 and42 as discussed above with respect to the present corner element 22 incombination with any of the fastener elements 46, 58 and 70 as explainedabove greatly improves the speed, accuracy, and overall strength andrigidity of connecting adjacent duct sections.

It should also be noted that the present connector elements 22 do notinclude any projections or other members which extend transverselyrelative to the top and bottom surfaces thereof such as the projectionsassociated with the angle plate illustrated in U.S. Pat. No. 5,342,100.As a result, the top and bottom surfaces of the corner elements 22 arerelatively smooth; they are easy to handle; they provide no projectionsor protrusions which can be hazardous to workers when handling thecorner elements or which can impede their work efficiency by gettingcaught in their work gloves or even cutting the worker's hand; they arenestable one on top of the other; and they are stackable in aconventional corner installing machine as illustrated in FIG. 12. Inthis regard, a plurality of the present corner elements 22 can bestacked and nested in a conventional corner installing machine such asthose manufactured by Iowa Processing Industries and/or Lockformer, andthe present corner elements 22 are easily slidable from the bottom of astacked arrangement for use in conventional corner installing machines.In this regard, a center support or riser such as the member 84illustrated in FIG. 12 can be provided or otherwise associated with aconventional automatic installing machine to provide support to thepresent corner elements 22 due to their bowed configuration.

In addition, as best illustrated in FIGS. 4 and 9, the width of thepresent corner elements 22 is such that crimping of the terminal endportion 20 of the duct channel side flange 18 is likewise possible tofurther strengthen the stability of the overall joinder and to furtherhold the pair of opposed corner elements 22 in proper position withinthe duct channel flanges 12 as previously explained. In this regard, thepresent corner elements 22 are sized and shaped so that no pressing ofthe corner elements 22 into a respective duct channel flange 12 isrequired, but the width of the respective leg portions 24 and 26 as bestshown in FIGS. 5 and 8 is such that crimping can be easily accomplished.Since the present corner elements 22 do not include upstanding sidewalls, crimping now requires the bending over of only one metalthickness, namely, the side wall or side flange 18 of the duct channelflange 12 onto the corner leg portions 24 and/or 26 instead of bendingover two metal thickness as is true with the angle plate disclosed inU.S. Pat. No. 5,342,100. This requires only one half of the force toaccomplish the bending as previously required and it saves time.

Still further, the duct sections 10 can be brought into end-to-endrelationship without having any corner flange connection membersinitially associated with either duct section. The present corner flangeconnection member 22 could be held manually in registration with theduct channel flanges 12 while any one of the fasteners 46, 58 and/or 70are driven through the opposed pair of corner elements 22 and/or theduct channel flanges 12. The opposite corner flange connection membercould be held in place at the same time until the appropriate fastenerhad simultaneously completed the task of securing each corner flangeconnection member 22 to its respective adjacent duct channel flange 12and thereby securing the duct sections 10 together. No special cornerflange connection members or other connection components, or any specialequipment including using a conventional corner installing machine isnecessary to complete the joinder of adjacent duct sections inaccordance with the present invention.

FIG. 13 illustrates another embodiment 86 of the present inventionwherein corner element 86 includes a pair of integrally formed legportions 88 and 90, a corner portion 92 having a pair of spaced apartopenings 94 associated therewith and a pair of optional openings 96associated with the respective leg portions 88 and 90. Corner element86, like corner element 22, likewise includes a pair of spaced creasesor bends 98 and 100 wherein the respective leg portions 88 and 90 aresimilarly bent or angularly deflected about such creases so as topresent the same bowed shaped configuration as previously discussed withrespect to corner element 22. Corner element 86 differs from cornerelement 22 in that the pair of openings 94 associated with cornerportion 92 are of the same diameter and the pair of openings 96associated with the respective leg portions are of the same diameter. Inthis regard, the diameter of the openings 96 may be of the same diameteras the openings 94, or they may be of a different diameter. In thisparticular embodiment, joinder of adjacent duct sections 10 and adjacentopposed corner elements 86 can be accomplished through the use of anyone of the fasteners 46, 58, 70 and/or a conventional nut and boltarrangement, the only difference being that the threaded portionassociated with any of these fastener members will bite into thematerial of the opposed corner elements 86 surrounding both pairs of theopenings 94 and/or 96 as the fastener is driven through such alignedopenings. In this regard, the threaded portion of the fastenerspositioned through openings 94 and/or 96 will be compatible with therespective diameters of such openings so as to form a threaded innerconnection between the opposed pairs of corner elements 86 as previouslyexplained with respect to corner element 22. Like corner element 22, thebowed configuration of corner element 86 provides the same increasedclamping pressure to the duct channel flanges when a pair of ductsections are joined together as previous explained regardless of whetherthe respective openings 94 are of the same size or of different sizes,and regardless of whether the openings 96 are of the same size or of adifferent size. Also, as previously discussed, corner portion 92 couldlikewise form a continuous bend or curve with leg portions 88 and 90such that corner element 86 is completely bowed.

When using any one of the fasteners 46, 58, 70, or any conventional nutand bolt arrangement to join together opposed connector elements 86 in atight sealing engagement with one another, it is known in the practiceto strip out the threads formed in the opening 94 and/or 96 associatedwith the first mating corner element 86 in a connected pair of cornerelements 86 in order to allow the threaded portion of the fastenermember to draw the second mating corner element 86 into tight engagementwith the first corner element 86. Once the first opening is stripped,further threading of the fastener through the opening associated withthe opposed mating corner element 86 will then draw such mating cornerelement into tight engagement with the first corner element. Thisstripping of the threads cut into the first opening is time consumingand inefficient.

In order to improve the joinder process where the aligned openings 94and/or 96 associated with corner element 86 are of the same diameter,another aspect of the present invention relates to a still furtherimproved high speed connection fastening member 102 illustrated in FIG.14. The fastener 102 includes a head portion 104, a relief portion 106,a threaded portion 108, and a piloted portion 110. The relief portion106 is positioned between the head portion 104 and the threaded portion108 and differs from the unthreaded portions 107 associated withfasteners 46, 58 and 70 in that the relief portion 106 is of a diameterequal to the root diameter of the threaded portion 108. This is not trueof portions 107 associated with fasteners 46, 58 and 70 wherein portions107 are of a diameter equal to the outside diameter of the respectivethreaded portions 50, 66 and 78. The piloted portion 110 of fastener 102also includes a beveled tip 112 for guiding and aligning the fastener102 within a respective opening as previously explained with respect tofasteners 46 and 68. The threaded portion 108 of fastener 102 is sizedand dimensioned in accordance with the diameter of the respectiveopenings 94 and/or 96 associated with the corner element 86 throughwhich it will be inserted.

Attachment of an opposed pair of corner elements 86 positioned withinadjacent duct channel flanges 12 is best illustrated in FIGS. 15 A-C. Inthis regard, the fastener 102 is first inserted through the opening 94associated with the first corner element 86 and threaded portion 108 isthreaded through opening 94 until the piloted portion 110 is receivedwithin the aligned opening 94 associated with the second mating opposedcorner element 86 as best illustrated in FIG. 15A. Since the pilotedportion 110 of the fastener 102 has a diameter likewise equal to theroot diameter of threaded portion 108, the piloted portion 110 offastener 102 will register and extend through the corresponding opening94. The fastener 102 will then continue to thread through both the firstopposed corner element 86 and the second opposed corner element 86 untilthe relief portion 106 of fastener 102 registers with and extendsthrough the opening 94 associated with the first corner element 86 asbest illustrated in FIG. 15B. Once the relief portion 106 is inregistration with the first opening 94 of the first corner element 86,further threading of the fastener 102 through the aligned opening 94associated with the second corner element 86 will now begin to draw thesecond mating corner plate 86 into a tight sealing/abutting relationshipwith the first opposed corner element 86 through the threading action ofthe fastener 102 as best illustrated in FIG. 15C. Since the reliefportion 106 has no threads associated therewith, stripping of theopening 94 is not necessary and as soon as the relief portion 106 offastener 102 registers with the opening 94 associated with the firstcorner element 86, further driving of the fastener member 102 into thesecond opposed corner element 86 will draw the second corner element 86into engagement with the first corner element 86 thereby completing thejoinder. Use of the fastener 102 therefore avoids stripping of thethreads formed in the first opening 96 and thereby speeds up the entireprocess. In FIGS. 15A-C, the side walls 18 of each respective ductchannel flange 12 are crimped onto the corresponding corner element 86.

Since the corner elements 86 are likewise of a bowed configuration, asthe fastener 102 is driven through the respective pair of cornerelements 86, the corner portions 92 of the opposed corner elements 86are likewise drawn together by the action of the fastener 102 therebyexerting an increased clamping or biasing force against the respectiveduct channel flanges 12 which further serves to form a tight sealingrelationship at the joint between the duct sections. Attachment of anadditional fastener 102 through the other aligned pair of openings 94associated with an opposed pair of connector elements 86 will functionand operate in a similar fashion as just described.

In those applications where additional strength and rigidity arenecessary for connecting adjacent duct sections 10, optional alignedopenings 96 associated with the respective leg portions 88 and 90 of theopposed pair of connector elements 86 can likewise be drawn into tightsealing engagement with each other through the use of a fastener membersimilar to fastener 102. In this regard, the threaded portion of afastener similar to fastener 102 would be sized and dimensioned so as tobe compatible with the diameter of the respective openings 96 so as todraw the duct sections 10 sandwiched therebetween into a tight sealingrelationship by the action of the fastener positioned therethrough suchas a fastener similar to fastener 102 in a manner as just explained.

It is also recognized that fastener 102 can be utilized in theattachment of opposed pairs of corner elements 22 and relief portion 106will function identically as the unthreaded portions 107 associated withfasteners 46, 58 and 70 during such joinder.

FIG. 16 illustrates still another embodiment 114 of the presentinvention wherein the corner element 114 is again basically L-shaped inconfiguration and includes a pair of integrally formed leg portions 116and 118 which are integrally joined together at corner portion 120.Corner element 114 is substantially similar to corner element 22 exceptthat corner element 114 is substantially flat and does not includecreases or bends 34 and 36 associated with corner element 22. Instead,leg portions 116 and 118 as well as corner portion 120 all lie insubstantially the same plane. However, similar to corner element 22,corner element 114 includes a pair of spaced apart openings 122 and 124,opening 122 being larger in diameter than opening 124, opening 122 beingsimilar to opening 30 and being characterized as a clearance hole whileopening 124 is similar to opening 32 and is characterized as being a taphole.

In similar fashion, the leg portions 116 and 118 of corner element 14may likewise each include an optional opening 126 and 128 as illustratedin FIG. 16, opening 126 being characterized as a clearance opening andopening 128 being characterized as a tap hole. Openings 126 and 128associated with corner element 114 are substantially similar to openings40 and 42 associated with corner element 22. In this regard, thediameters of the clearance holes 122 and 126 and the tap holes 124 and128 are as previously explained with respect to corner element 22 anduse of any one of the fasteners 46, 58, 70, 102, and a conventional nutand bolt arrangement can be utilized as explained above with respect tocorner elements 22 and 86 when attaching aligned opposed pairs of cornerelements 114 for connecting adjacent end-to-end duct sections 110 aspreviously explained. Since the corner element 114 is substantiallyflat, it is possible to orient opposed corner elements 114 in opposedduct channel flanges 12 such that the clearance openings 122 and 126associated with one of the aligned pair of corner elements 114 isaligned with the clearance opening 122 and 126 associated with theopposed pair of corner elements 114. As a result, care must be takensuch that the opposed aligned pairs of corner elements 114 arepositioned within their corresponding duct channel flanges 12 such thatthe clearance openings 122 and 126 of one corner element 114 will bealigned with the tap openings 124 and 128 associated with the otheraligned corner element 114. In all other respects, attachment of alignedpairs of corner elements 114 will be substantially similar to thatpreviously described with respect to channel element 22 except that theadditional clamping force achieved from the bowed configuration ofcorner element 22 will not be realized with the substantially flatcorner element 114.

In order to eliminate the possibility of improperly orienting opposedpairs of corner elements 114 as previously explained, the respectivecorner openings 122 and 124 could be made of the same diameter and theleg openings 126 and 128 could be made of a similar diameter. FIG. 17therefore illustrates still another embodiment 130 of the present cornerelement wherein the corner element 130 is substantially similar tocorner element 114 except that the openings 132 associated with cornerportion 134 are of the same diameter and the openings 136 associatedrespectively with the leg portions 138 and 140 are of the same diameter.As previously explained with respect to corner element 86, the diameterof the openings 132 may be the same as or different from the diameter ofthe openings 136. In all other respects, the function and operation ofthe corner element 130 is substantially identical to the function andoperation of the corner element 114 and attachment of an aligned pair ofcorner elements 130 can be quickly and easily accomplished through theuse of the high speed piloted fastener 102 as previously explained withrespect to corner element 86. Since the openings 132 and 136 are ofsimilar diameter, corner openings 132 and leg openings 136 associatedwith one aligned pair of corner elements 130 will always be inregistration with similar openings 132 and 136 associated with the otheraligned pair of corner elements 130 regardless of the orientation of thecorner element 130 when positioned within the corresponding duct channelflange 12. This embodiment eliminates misalignment of the respectivealigned openings associated with the corner elements since the diameterof such openings are the same.

FIG. 18 illustrates still another embodiment 142 on the presentinvention wherein the corner element 142 is substantially similar tocorner element 22 except that the pair of corner openings 30 and 32 havebeen replaced with a single corner opening 144. Corner opening 144 issubstantially rectangular in shape and is adapted to receive a standardcarriage bolt typically used in the industry. In all other respects, thecorner element 142 is substantially identical to corner element 22 andincludes a pair of integrally formed leg portions 146 and 148 which areintegrally joined at corner portion 150; a pair of optional leg openings152 and 154, opening 152 being a clearance opening and opening 154 beinga tap opening; and a pair of spaced creases or bends 156 and 158 aboutwhich the respective leg portions 146 and 148 are similarly bent orangularly deflected as previously explained so as to present the samebowed shaped configuration previously discussed with respect to cornerelement 22.

Joinder of adjacent duct sections utilizing adjacent opposed cornerelements 142 can be accomplished through the use a conventional carriagetype bolt. In this regard, FIG. 19 illustrates still another embodiment160 of a high-speed fastener member for use with the present cornerelements 142, the embodiment 160 including a standard carriage bolt 162and a piloted nut 164. The standard carriage bolt 162 includes a headportion 166, a rectangularly shaped relief portion 168, and a threadedportion 170. The piloted nut 164 includes a non-threaded cavity 172 anda threaded cavity 174. The non-threaded cavity 172 is of a diameterlarger than the threaded portion 170 of carriage bolt 162 and largerthan threaded cavity 174 and extends along a portion of the overalllength of the piloted nut 164 as illustrated in FIG. 19. Similar tofastener member 70 illustrated in FIG. 11, the slightly oversizednon-threaded cavity 172 serves as a guide mechanism for properlyorienting the threaded portion 170 of the standard carriage bolt 162into the nut 164 before engaging the threaded cavity 174. In thisregard, the piloted nut 164 functions and operates substantially similarto piloted nut 74 illustrated in FIG. 11, thereby again substantiallyeliminating cross-threading and misalignment issues in engaging the nut164 with the carriage bolt 162.

It is also recognized that the piloted nut 164 may also include a flatwasher shaped portion attached or otherwise associated with one endportion thereof thereby forming a piloted washered nut for use withslotted or rectangular openings. In this regard, the corner opening 144associated with corner element 142 may be square instead of rectangular,or it may take on any other shape other than a circular shape, and therelief portion 168 associated with the carriage bolt 162 will have ashape compatible with the shape of the corner opening 144.

Still further, in this regard, the corner element 142 could likewise bea substantially flat corner element similar to the flat shape associatedwith corner elements 114 and 130. Use of the fastener 160 in conjunctionwith corner element 142 again provides for a quick, easy, and high-speedconnection between the carriage bolt 162 and the nut 164 includingperforming such connection through the use of a power tool. In addition,use of the clearance hole 152 and the tap hole 154 as discussed abovewith respect to corner element 22 in combination with any of thefastener elements 46, 58 and 70 as explained above likewise greatlyimproves the speed, accuracy, and overall strength and rigidity of theconnecting adjacent duct sections. High-speed fastener 160 thereforeaccommodates use of a rectangular or square opening commonly associatedwith corner elements such as the rectangular opening 144 associated withcorner element 142. It is further recognized and anticipated that thecarriage bolt 162 could likewise include a piloted portion similar topiloted portion 52 or 68 to further guide the carriage bolt 162 intoproper engagement with the nut 164. In this regard, if a piloted endportion is associated with the carriage bolt 162, a conventional nutcould be used instead of the piloted nut 164 as previously explainedwith respect to the high-speed fastener 58.

FIG. 20 illustrates still another embodiment 176 of the presentinvention wherein the corner element 176 is substantially similar tocorner element 142 except that the substantially rectangularly corneropening 144 has been replaced with an oblong opening 178 which isadapted to receive an improved high speed fastening member 204 as bestillustrated in FIG. 21. Like corner element 142, corner flangeconnection member 176 likewise includes a pair of integrally formed legportions 180 and 182 which are integrally joined at corner portion 184,a pair of optional leg openings 186 and 188, and a pair of spacedcreases or bends 190 and 192 about which the respective leg portions 180and 182 are similarly bent or angularly deflected as previouslyexplained so as to present the same bowed shaped configurationpreviously discussed with respect to corner element 22. Optional legopenings 186 and 188 can be of the same diameter, or opening 186 can bea clearance opening and opening 188 can be a tap opening as previouslyexplained. The oblong opening 178 extending through the corner portion184 is derived from overlaying and offsetting two circles equal to theroot diameter of the threaded portion 210 associated with fasteningmember 204 illustrated in FIG. 21. The forming of the opening 178 isbest illustrated in FIG. 22 wherein two circles having the root diameterof the threaded portion 210 of fastener 204 are overlaid and offset adistance equal to the thread height of the threads 214 associated withthreaded portion 210 as best illustrated in FIGS. 21 and 22. Once thetwo circles in FIG. 22 are overlaid and offset as explained andillustrated, the inner arc portions 194 and 196 (FIG. 22) are eliminatedand substantially tangent lines 198 and 200 are drawn connecting thesides of the two circles thereby forming the oblong opening 178. Thelines 198 and 200 do not have to be exact tangent lines but can beapproximately tangent and still achieve the desired results.Importantly, the centers associated with the two circles illustrated inFIG. 22 are in alignment with each other and lie on line 202, thesecenters being offset as previously explained by the height of thethreads associated with fastening member 204. The resulting opening 178is illustrated in FIG. 20 and its arcuate end portions have a radiusequal to the radius of the root diameter of threaded portion 210 offastener 204.

Joinder of adjacent duct sections utilizing adjacent opposed cornerflange connection members 176 can be accomplished through the use offastening member 204 illustrated in FIG. 21. Fastening member 204 isspecifically designed for use with corner element 176 and, moreparticularly, with the opening 178 and includes a head portion 206, anon-threaded spinout area 208, a threaded portion 210 and a blunt orflat terminal end portion 212. The non-threaded spinout area 208 ispositioned between head portion 206 and the start of the threadedportion 210 and its length is typically equal to at least the thicknessof the corner portion 184 of corner element 176. In addition, thespacing between the threads 214 associated with threaded portion 210 areequal to approximately twice the thickness of the corner portion 184 ofcorner element 176. These parameters enable the fastening member 204 tobe positioned within the opening 178 at a slight angle of insertion suchthat the outside diameter of the threads 214 on one side of the fastenermember 204 clears the opening 178 while the root diameter of thethreaded portion 210 associated with the opposite side portion offastening member 204 clears or abuts the opposite side of opening 178.This enables the fastening member 204 to be inserted within the opening178 of a first opposed corner element 176 at a slight inclination andthereafter threaded through opening 178 of the first opposed cornerelement, through corresponding openings associated with the duct channelflange pairs sandwiched therebetween, until the blunt end portion 212 ofthe fastening member 204 is received within the corresponding opening178 associated with the second mating opposed corner element 176. Thefastener 204 will then continue to be threaded through both the firstopposed corner element 176 and the second opposed corner element 176until the spinout area 208 of fastener 204 registers with and extendsthrough the opening 178 associated with the first corner element 178 aspreviously explained with respect to fastener 102 illustrated in FIGS.15A-C. Once the spinout area 208 is in registration with the firstopening 178 of the first corner element 176, further threading of thefastener 204 through the aligned opening 178 associated with the secondcorner element 176 will now begin to draw the second mating cornerflange connection member 176 into a tight sealing/abutting relationshipwith the first opposed corner element 176 through the threading actionof the fastener 204. Like fastener 102, use of the fastening member 204avoids stripping of the threads formed in the first opening 178 andthereby speeds up the entire process. Also, as the fastening member 204begins to thread itself through the second opening 178 associated withthe second corner element 176, the fastening member 204 will straightenitself out and become substantially vertical as the threading operationis completed. The new fastening member 204 includes the same attributesas explained above with respect to fastener 102 but is specificallydesigned as a sheet metal fastener for use with sheet metal typicallyused in the HVAC industry.

Since the corner elements 176 are likewise of a bowed configuration, asthe fastening member 204 is driven through the respective pair of cornerelements 176, the corner portions 184 of the opposed corner elements arelikewise drawn together by the action of the fastening member 204thereby exerting an increased clamping or biasing force against therespective duct channel flanges which further serves to form a tightsealing relationship at the joint between the duct sections. It is alsorecognized that the corner element 176 could be completely bowed aspreviously explained and opening 178 could be formed and positioned onbowed corner portion 184 as previously explained. It is furtherrecognized that the corner element 176 could likewise be constructed asa substantially flat member and still function in a conventional mannerwith fastening member 204 drawing the opposed corner elements 176 intotight engagement with each other.

It is also recognized that the fastener 204 could likewise be utilizedwith a piloted nut similar in construction to the piloted nut 74illustrated in FIG. 11 wherein the piloted nut would include anon-threaded cavity and a threaded cavity designed to guide, receive andaccept threaded portion 210 of fastener member 204.

Like connector element 22, it should be noted that connector elements86, 114, 130, 142 and 176 likewise do not include any projections orother members which extend transversely relative to the top and bottomsurfaces thereof, and they are likewise stackable and nestable in aconventional corner installing machine as previously explained withrespect to corner element 22. Since corner elements 114 and 130 aresubstantially flat, the use of a center support or riser member such asmember 84 illustrated in FIG. 12 will not be necessary.

In similar fashion, as with corner element 22, the width of the cornerelements 86, 114, 130, 142 and 176 are likewise such that crimping ofthe terminal end portion 20 of the duct channel side flange 18 islikewise possible to further strengthen the stability of the overalljoinder and to further hold the pair of opposed corner elements inproper position within the duct channel flanges 12 as previouslyexplained.

The present corner flange connection members 22, 86 114, 130, 142 and176 and the connection systems described herein provide not onlysubstantial strength to the joined duct section corners, but when theopenings associated with the leg portions thereof are utilized, itlikewise physically joins the adjacent side walls of each duct section10. The strength arises from the integral connection of the cornerelements to the adjacent duct channel flanges at the intersection of thecorners of the duct sections 10 by the high-speed fasteners 46, 58, 70,102, 160 and/or 204 extending through the corner portions of eachrespective pair of corner elements. More particularly, the unique bowedconfiguration of the present corner elements 22, 86, 142 and 176 providefor a greater clamping force to the respective duct channel flangesduring the fastening process as compared to the known conventional angleplates used in the industry. This spring-type biasing force achieved viathe bowed configuration increases the strength and rigidity of thejoined duct sections. As a result, a stronger corner-to-corner clampingforce is generated through the use of the present corner elements 22,86, 142 and 176. In addition, through the use of the high-speed fastenermembers disclosed herein, joinder of an opposed pair of corner elementscan be made with just a single fastener member, namely, any one of thefasteners 46, 58, 70, 102, 160 or 204 as opposed to the use of aconventional bolt/washer/nut arrangement typically and commonly used inthe industry today. In addition, use of all of the disclosed high-speedfastener members substantially eliminate cross-threading andmisalignment of conventional nuts and bolts during the fastening processand all of the fasteners 46, 58, 70, 102, 160 and 204 greatly improvethe speed and time necessary to accomplish the connection. In addition,all such high-speed fastener members disclosed herein are adaptable foruse with power tools thereby further increasing the speed and efficiencyof making such connections as compared to conventional bolt/nutcombinations. Still further, the self-aligning features associated withthe fasteners 46, 58, 70, 102, 142 and 204 likewise improve theefficiency of the fastening process as compared to the use ofconventional bolts and nuts.

Use of the present high-speed fasteners likewise eliminates adjacentduct sections from being fastened out of square or out of alignment dueto manufacturing tolerances and shipping deformation. In this regard,use of corresponding slots in the duct channel flanges in combinationwith the holes associated with the leg portions of the present cornerelements likewise allow for duct channel flange size variations withoutprecluding the insertion and tightening of the piloted fastening members46, 58, 70, 102, 160 and 204. Duct work is actually more often than notmade with plus and minus sizes that will not allow any pre-formed holesin the duct flanges to line up accurately from duct flange to ductflange as well as to line up accurately with holes associated withcorner or angle plates, all which causes the installer to be required tohand drill an opening through the misaligned holes thus compromising thequality of the connection desired and also increasing the laborinvolved. Use of the present corner elements as well as the presenthigh-speed fasteners helps to eliminate this problem. In addition, thepresent corner elements can be easily adjusted to align duct sectionsthat are slightly over or under sized. Since the present corner elementsinclude no protrusions or sharp edges, they can be easily nested andstacked for use in automated corner installing machines.

Sheet metal workers are required to assemble and hang duct work sectionsfor the most part well above the ground floor level in buildings andother structures. The spirit of the present invention allows thatprocess to proceed much easier and faster which minimizes a workersfrustration and allows for a more friendly work environment wheninstalling and connecting duct sections together. The use of any one ofthe present high-speed fastener members and a power tool allows theassembly to be accomplished without use of conventional bolts, nuts andwashers thereby bringing the entire installation and joinder operationback into the familiar sheet metal worker's field of expertise.

These and other advantages associated with the present corner elements22, 86, 114, 130, 142 and 176, the present fasteners 46, 58, 70, 102,160 and 204, and the various methods for attaching the various cornerelements to adjacent duct sections will be readily apparent to a personskilled in the art and other various changes and modifications could bemade in the above constructions without departing from the spirit andscope of the present invention.

What is claimed is:
 1. A corner flange connection member adapted forjoining together adjacent duct channel flanges associated with ductsections, said corner flange connection member comprising two legportions joined together in an angular relationship by a corner portion,said connection member being substantially flat and including at leastone opening for joining duct sections, and at least one fastening memberhaving a threaded portion associated therewith, said at least oneopening being formed by overlaying and offsetting two openings aboutequal to the root diameter of the threaded portion of said at least onefastening member, the offset distance between the centers of the twoopenings being about equal to the thread height of the threadsassociated with said at least one fastening member, the sides of saidopenings being formed by joining each of said side of said offsetopenings with a respective substantially tangent line.
 2. The cornerflange connection member defined in claim 1 wherein said at least onefastening member includes a head portion, a non-threaded spinoutportion, a threaded portion, a threaded piloting lead in portion, and ablunt terminal end portion, said spinout portion being positionedbetween said head portion and said threaded portion and being of alength about equal to at least the thickness of said corner portion. 3.The corner flange connection member defined in claim 1 wherein spacingbetween adjacent threads of the fastening member is about equal toapproximately twice a thickness of said corner portion.
 4. The cornerflange connection member defined in claim 1 wherein at least one of saidleg portions includes at least one bend.
 5. A corner flange connectionmember adapted for joining together adjacent duct channel flanges ofduct sections, said corner flange connection member comprising two legportions joined together in an angular relationship by a corner portion,said connection member being substantially flat and including at leastone opening therethrough for joining the duct sections, and at least onefastening member having a threaded portion, the threaded portion havinga root diameter, said at least one opening being defined by two joinedand offset partially rounded openings, at least one of the offsetpartially rounded openings having a sectional extent between oppositesides thereof about equal to the root diameter of the threaded portionof said at least one fastening member, the offset of the two openingsbeing about equal to a thread height of threads of the threaded portionof the fastening member, and the sides of said offset openings beingjoined generally tangentially.
 6. The corner flange connection memberdefined in claim 5 wherein said at least one fastening member includes ahead portion, a non-threaded spinout portion, the threaded portion, athreaded piloting lead in portion, and a blunt terminal end portion,said spinout portion being positioned between said head portion and saidthreaded portion and being of a length about equal to at least athickness of said corner portion.
 7. The corner flange connection memberdefined in claim 6 wherein a spacing between adjacent threads of thethreaded portion of at least one fastening member is about equal toapproximately twice the thickness of said corner portion.
 8. The cornerflange connection member defined in claim 5 wherein at least one of saidleg portions includes at least one bend.